#include "tiffiop.h"
#ifdef CCITT_SUPPORT

#include "tif_fax3.h"
#define G3CODES
#include "t4.h"
#include <assert.h>
#include <stdio.h>

/*
   Compression+decompression state blocks are
   derived from this ``base state'' block.
*/
typedef struct {
  int     rw_mode;                /* O_RDONLY for decode, else encode */
  int mode;     /* operating mode */
  uint32  rowbytes;   /* bytes in a decoded scanline */
  uint32  rowpixels;    /* pixels in a scanline */

  uint16  cleanfaxdata;   /* CleanFaxData tag */
  uint32  badfaxrun;    /* BadFaxRun tag */
  uint32  badfaxlines;    /* BadFaxLines tag */
  uint32  groupoptions;   /* Group 3/4 options tag */
  uint32  recvparams;   /* encoded Class 2 session params */
  char* subaddress;   /* subaddress string */
  uint32  recvtime;   /* time spent receiving (secs) */
  TIFFVGetMethod vgetparent;  /* super-class method */
  TIFFVSetMethod vsetparent;  /* super-class method */
} Fax3BaseState;
#define Fax3State(tif)    ((Fax3BaseState*) (tif)->tif_data)

typedef enum { G3_1D, G3_2D } Ttag;
typedef struct {
  Fax3BaseState b;

  /* Decoder state info */
  const u_char* bitmap;   /* bit reversal table */
  uint32  data;     /* current i/o byte/word */
  int bit;      /* current i/o bit in byte */
  int EOLcnt;     /* count of EOL codes recognized */
  TIFFFaxFillFunc fill;   /* fill routine */
  uint32* runs;     /* b&w runs for current/previous row */
  uint32* refruns;    /* runs for reference line */
  uint32* curruns;    /* runs for current line */

  /* Encoder state info */
  Ttag    tag;                  /* encoding state */
  u_char* refline;    /* reference line for 2d decoding */
  int k;      /* #rows left that can be 2d encoded */
  int maxk;     /* max #rows that can be 2d encoded */
} Fax3CodecState;
#define DecoderState(tif) ((Fax3CodecState*) Fax3State(tif))
#define EncoderState(tif) ((Fax3CodecState*) Fax3State(tif))

#define is2DEncoding(sp) \
  (sp->b.groupoptions & GROUP3OPT_2DENCODING)
#define isAligned(p,t)  ((((u_long)(p)) & (sizeof (t)-1)) == 0)

/*
   Group 3 and Group 4 Decoding.
*/

/*
   These macros glue the TIFF library state to
   the state expected by Frank's decoder.
*/
#define DECLARE_STATE(tif, sp, mod)         \
  static const char module[] = mod;         \
  Fax3CodecState* sp = DecoderState(tif);       \
  int a0;       /* reference element */   \
  int lastx = sp->b.rowpixels;  /* last element in row */ \
  uint32 BitAcc;      /* bit accumulator */   \
  int BitsAvail;      /* # valid bits in BitAcc */  \
  int RunLength;      /* length of current run */ \
  u_char* cp;       /* next byte of input data */ \
  u_char* ep;       /* end of input data */   \
  uint32* pa;       /* place to stuff next run */ \
  uint32* thisrun;      /* current row's run array */ \
  int EOLcnt;       /* # EOL codes recognized */  \
  const u_char* bitmap = sp->bitmap;  /* input data bit reverser */ \
  const TIFFFaxTabEnt* TabEnt
#define DECLARE_STATE_2D(tif, sp, mod)          \
  DECLARE_STATE(tif, sp, mod);          \
  int b1;       /* next change on prev line */  \
  uint32* pb        /* next run in reference line */\
  /*
     Load any state that may be changed during decoding.
  */
#define CACHE_STATE(tif, sp) do {         \
    BitAcc = sp->data;              \
    BitsAvail = sp->bit;            \
    EOLcnt = sp->EOLcnt;            \
    cp = (unsigned char*) tif->tif_rawcp;       \
    ep = cp + tif->tif_rawcc;           \
  } while (0)
/*
   Save state possibly changed during decoding.
*/
#define UNCACHE_STATE(tif, sp) do {         \
    sp->bit = BitsAvail;            \
    sp->data = BitAcc;              \
    sp->EOLcnt = EOLcnt;            \
    tif->tif_rawcc -= (tidata_t) cp - tif->tif_rawcp;     \
    tif->tif_rawcp = (tidata_t) cp;         \
  } while (0)

/*
   Setup state for decoding a strip.
*/
static int
Fax3PreDecode( TIFF* tif, tsample_t s ) {
  Fax3CodecState* sp = DecoderState( tif );
  ( void ) s;
  assert( sp != NULL );
  sp->bit = 0;      /* force initial read */
  sp->data = 0;
  sp->EOLcnt = 0;     /* force initial scan for EOL */
  /*
     Decoder assumes lsb-to-msb bit order.  Note that we select
     this here rather than in Fax3SetupState so that viewers can
     hold the image open, fiddle with the FillOrder tag value,
     and then re-decode the image.  Otherwise they'd need to close
     and open the image to get the state reset.
  */
  sp->bitmap =
    TIFFGetBitRevTable( tif->tif_dir.td_fillorder != FILLORDER_LSB2MSB );
  if( sp->refruns ) {   /* init reference line to white */
    sp->refruns[0] = ( uint32 ) sp->b.rowpixels;
    sp->refruns[1] = 0;
  }
  return ( 1 );
}

/*
   Routine for handling various errors/conditions.
   Note how they are "glued into the decoder" by
   overriding the definitions used by the decoder.
*/

static void
Fax3Unexpected( const char* module, TIFF* tif, uint32 a0 ) {
  TIFFError( module, "%s: Bad code word at scanline %d (x %lu)",
             tif->tif_name, tif->tif_row, ( u_long ) a0 );
}
#define unexpected(table, a0) Fax3Unexpected(module, tif, a0)

static void
Fax3Extension( const char* module, TIFF* tif, uint32 a0 ) {
  TIFFError( module,
             "%s: Uncompressed data (not supported) at scanline %d (x %lu)",
             tif->tif_name, tif->tif_row, ( u_long ) a0 );
}
#define extension(a0) Fax3Extension(module, tif, a0)

static void
Fax3BadLength( const char* module, TIFF* tif, uint32 a0, uint32 lastx ) {
  TIFFWarning( module, "%s: %s at scanline %d (got %lu, expected %lu)",
               tif->tif_name,
               a0 < lastx ? "Premature EOL" : "Line length mismatch",
               tif->tif_row, ( u_long ) a0, ( u_long ) lastx );
}
#define badlength(a0,lastx) Fax3BadLength(module, tif, a0, lastx)

static void
Fax3PrematureEOF( const char* module, TIFF* tif, uint32 a0 ) {
  TIFFWarning( module, "%s: Premature EOF at scanline %d (x %lu)",
               tif->tif_name, tif->tif_row, ( u_long ) a0 );
}
#define prematureEOF(a0)  Fax3PrematureEOF(module, tif, a0)

#define Nop

/*
   Decode the requested amount of G3 1D-encoded data.
*/
static int
Fax3Decode1D( TIFF* tif, tidata_t buf, tsize_t occ, tsample_t s ) {
  DECLARE_STATE( tif, sp, "Fax3Decode1D" );
  ( void ) s;
  CACHE_STATE( tif, sp );
  thisrun = sp->curruns;
  while( ( long )occ > 0 ) {
    a0 = 0;
    RunLength = 0;
    pa = thisrun;
    #ifdef FAX3_DEBUG
    printf( "\nBitAcc=%08X, BitsAvail = %d\n", BitAcc, BitsAvail );
    printf( "-------------------- %d\n", tif->tif_row );
    fflush( stdout );
    #endif
    SYNC_EOL( EOF1D );
    EXPAND1D( EOF1Da );
    ( *sp->fill )( buf, thisrun, pa, lastx );
    buf += sp->b.rowbytes;
    occ -= sp->b.rowbytes;
    continue;
  EOF1D:        /* premature EOF */
    CLEANUP_RUNS();
  EOF1Da:       /* premature EOF */
    ( *sp->fill )( buf, thisrun, pa, lastx );
    UNCACHE_STATE( tif, sp );
    return ( -1 );
  }
  UNCACHE_STATE( tif, sp );
  return ( 1 );
}

#define SWAP(t,a,b) { t x; x = (a); (a) = (b); (b) = x; }
/*
   Decode the requested amount of G3 2D-encoded data.
*/
static int
Fax3Decode2D( TIFF* tif, tidata_t buf, tsize_t occ, tsample_t s ) {
  DECLARE_STATE_2D( tif, sp, "Fax3Decode2D" );
  int is1D;     /* current line is 1d/2d-encoded */
  ( void ) s;
  CACHE_STATE( tif, sp );
  while( ( long )occ > 0 ) {
    a0 = 0;
    RunLength = 0;
    pa = thisrun = sp->curruns;
    #ifdef FAX3_DEBUG
    printf( "\nBitAcc=%08X, BitsAvail = %d EOLcnt = %d",
            BitAcc, BitsAvail, EOLcnt );
    #endif
    SYNC_EOL( EOF2D );
    NeedBits8( 1, EOF2D );
    is1D = GetBits( 1 ); /* 1D/2D-encoding tag bit */
    ClrBits( 1 );
    #ifdef FAX3_DEBUG
    printf( " %s\n-------------------- %d\n",
            is1D ? "1D" : "2D", tif->tif_row );
    fflush( stdout );
    #endif
    pb = sp->refruns;
    b1 = *pb++;
    if( is1D ) {
      EXPAND1D( EOF2Da );
    } else
    { EXPAND2D( EOF2Da ); }
    ( *sp->fill )( buf, thisrun, pa, lastx );
    SETVAL( 0 );  /* imaginary change for reference */
    SWAP( uint32*, sp->curruns, sp->refruns );
    buf += sp->b.rowbytes;
    occ -= sp->b.rowbytes;
    continue;
  EOF2D:        /* premature EOF */
    CLEANUP_RUNS();
  EOF2Da:       /* premature EOF */
    ( *sp->fill )( buf, thisrun, pa, lastx );
    UNCACHE_STATE( tif, sp );
    return ( -1 );
  }
  UNCACHE_STATE( tif, sp );
  return ( 1 );
}
#undef SWAP

/*
   The ZERO & FILL macros must handle spans < 2*sizeof(long) bytes.
   For machines with 64-bit longs this is <16 bytes; otherwise
   this is <8 bytes.  We optimize the code here to reflect the
   machine characteristics.
*/
#if defined(__alpha) || (defined(_MIPS_SZLONG) && _MIPS_SZLONG == 64) || defined(__LP64__) || defined(__arch64__)
#define FILL(n, cp)                 \
  switch (n) {                  \
  case 15:(cp)[14] = 0xff; case 14:(cp)[13] = 0xff; case 13: (cp)[12] = 0xff;\
  case 12:(cp)[11] = 0xff; case 11:(cp)[10] = 0xff; case 10: (cp)[9] = 0xff;\
  case  9: (cp)[8] = 0xff; case  8: (cp)[7] = 0xff; case  7: (cp)[6] = 0xff;\
  case  6: (cp)[5] = 0xff; case  5: (cp)[4] = 0xff; case  4: (cp)[3] = 0xff;\
  case  3: (cp)[2] = 0xff; case  2: (cp)[1] = 0xff;           \
  case  1: (cp)[0] = 0xff; (cp) += (n); case 0:  ;            \
  }
#define ZERO(n, cp)             \
  switch (n) {              \
  case 15:(cp)[14] = 0; case 14:(cp)[13] = 0; case 13: (cp)[12] = 0;  \
  case 12:(cp)[11] = 0; case 11:(cp)[10] = 0; case 10: (cp)[9] = 0; \
  case  9: (cp)[8] = 0; case  8: (cp)[7] = 0; case  7: (cp)[6] = 0; \
  case  6: (cp)[5] = 0; case  5: (cp)[4] = 0; case  4: (cp)[3] = 0; \
  case  3: (cp)[2] = 0; case  2: (cp)[1] = 0;             \
  case  1: (cp)[0] = 0; (cp) += (n); case 0:  ;     \
  }
#else
#define FILL(n, cp)                 \
  switch (n) {                  \
  case 7: (cp)[6] = 0xff; case 6: (cp)[5] = 0xff; case 5: (cp)[4] = 0xff; \
  case 4: (cp)[3] = 0xff; case 3: (cp)[2] = 0xff; case 2: (cp)[1] = 0xff; \
  case 1: (cp)[0] = 0xff; (cp) += (n); case 0:  ;         \
  }
#define ZERO(n, cp)             \
  switch (n) {              \
  case 7: (cp)[6] = 0; case 6: (cp)[5] = 0; case 5: (cp)[4] = 0;  \
  case 4: (cp)[3] = 0; case 3: (cp)[2] = 0; case 2: (cp)[1] = 0;  \
  case 1: (cp)[0] = 0; (cp) += (n); case 0:  ;      \
  }
#endif

/*
   Bit-fill a row according to the white/black
   runs generated during G3/G4 decoding.
*/
void
_TIFFFax3fillruns( u_char* buf, uint32* runs, uint32* erun, uint32 lastx ) {
  static const unsigned char _fillmasks[] =
  { 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff };
  u_char* cp;
  uint32 x, bx, run;
  int32 n, nw;
  long* lp;
  if( ( erun - runs ) & 1 ) {
    *erun++ = 0;
  }
  x = 0;
  for( ; runs < erun; runs += 2 ) {
    run = runs[0];
    if( x + run > lastx || run > lastx ) {
      run = runs[0] = ( uint32 )( lastx - x );
    }
    if( run ) {
      cp = buf + ( x >> 3 );
      bx = x & 7;
      if( run > 8 - bx ) {
        if( bx ) {    /* align to byte boundary */
          *cp++ &= 0xff << ( 8 - bx );
          run -= 8 - bx;
        }
        if( ( n = run >> 3 ) != 0 ) { /* multiple bytes to fill */
          if( ( n / sizeof( long ) ) > 1 ) {
            /*
               Align to longword boundary and fill.
            */
            for( ; n && !isAligned( cp, long ); n-- )
            { *cp++ = 0x00; }
            lp = ( long* ) cp;
            nw = ( int32 )( n / sizeof( long ) );
            n -= nw * sizeof( long );
            do {
              *lp++ = 0L;
            } while( --nw );
            cp = ( u_char* ) lp;
          }
          ZERO( n, cp );
          run &= 7;
        }
        if( run ) {
          cp[0] &= 0xff >> run;
        }
      } else
      { cp[0] &= ~( _fillmasks[run] >> bx ); }
      x += runs[0];
    }
    run = runs[1];
    if( x + run > lastx || run > lastx ) {
      run = runs[1] = lastx - x;
    }
    if( run ) {
      cp = buf + ( x >> 3 );
      bx = x & 7;
      if( run > 8 - bx ) {
        if( bx ) {    /* align to byte boundary */
          *cp++ |= 0xff >> bx;
          run -= 8 - bx;
        }
        if( ( n = run >> 3 ) != 0 ) { /* multiple bytes to fill */
          if( ( n / sizeof( long ) ) > 1 ) {
            /*
               Align to longword boundary and fill.
            */
            for( ; n && !isAligned( cp, long ); n-- )
            { *cp++ = 0xff; }
            lp = ( long* ) cp;
            nw = ( int32 )( n / sizeof( long ) );
            n -= nw * sizeof( long );
            do {
              *lp++ = -1L;
            } while( --nw );
            cp = ( u_char* ) lp;
          }
          FILL( n, cp );
          run &= 7;
        }
        if( run ) {
          cp[0] |= 0xff00 >> run;
        }
      } else
      { cp[0] |= _fillmasks[run] >> bx; }
      x += runs[1];
    }
  }
  assert( x == lastx );
}
#undef  ZERO
#undef  FILL

static char *
CheckMalloc( TIFF* tif, size_t nmemb, size_t elem_size, const char* what ) {
  char  *cp = NULL;
  tsize_t bytes = nmemb * elem_size;
  if( nmemb && elem_size && bytes / elem_size == nmemb ) {
    cp = ( char* ) _TIFFmalloc( bytes );
  }
  if( cp == NULL ) {
    TIFFError( tif->tif_name, "No space %s", what );
  }
  return ( cp );
}

/*
   Setup G3/G4-related compression/decompression state
   before data is processed.  This routine is called once
   per image -- it sets up different state based on whether
   or not decoding or encoding is being done and whether
   1D- or 2D-encoded data is involved.
*/
static int
Fax3SetupState( TIFF* tif ) {
  TIFFDirectory* td = &tif->tif_dir;
  Fax3BaseState* sp = Fax3State( tif );
  long rowbytes, rowpixels;
  int needsRefLine;
  Fax3CodecState* dsp = DecoderState( tif );
  uint32 nruns;
  if( td->td_bitspersample != 1 ) {
    TIFFError( tif->tif_name,
               "Bits/sample must be 1 for Group 3/4 encoding/decoding" );
    return ( 0 );
  }
  /*
     Calculate the scanline/tile widths.
  */
  if( isTiled( tif ) ) {
    rowbytes = TIFFTileRowSize( tif );
    rowpixels = td->td_tilewidth;
  } else {
    rowbytes = TIFFScanlineSize( tif );
    rowpixels = td->td_imagewidth;
  }
  sp->rowbytes = ( uint32 ) rowbytes;
  sp->rowpixels = ( uint32 ) rowpixels;
  /*
     Allocate any additional space required for decoding/encoding.
  */
  needsRefLine = (
                   ( sp->groupoptions & GROUP3OPT_2DENCODING ) ||
                   td->td_compression == COMPRESSION_CCITTFAX4
                 );
  nruns = needsRefLine ? 2 * TIFFroundup( rowpixels, 32 ) : rowpixels;
  dsp->runs = ( uint32* ) CheckMalloc( tif, 2 * nruns + 3, sizeof( uint32 ),
                                       "for Group 3/4 run arrays" );
  if( dsp->runs == NULL ) {
    return ( 0 );
  }
  dsp->curruns = dsp->runs;
  if( needsRefLine ) {
    dsp->refruns = dsp->runs + ( nruns >> 1 );
  } else
  { dsp->refruns = NULL; }
  if( is2DEncoding( dsp ) ) { /* NB: default is 1D routine */
    tif->tif_decoderow = Fax3Decode2D;
    tif->tif_decodestrip = Fax3Decode2D;
    tif->tif_decodetile = Fax3Decode2D;
  }
  if( needsRefLine ) {  /* 2d encoding */
    Fax3CodecState* esp = EncoderState( tif );
    /*
       2d encoding requires a scanline
       buffer for the ``reference line''; the
       scanline against which delta encoding
       is referenced.  The reference line must
       be initialized to be ``white'' (done elsewhere).
    */
    esp->refline = ( u_char* ) _TIFFmalloc( rowbytes );
    if( esp->refline == NULL ) {
      TIFFError( "Fax3SetupState",
                 "%s: No space for Group 3/4 reference line",
                 tif->tif_name );
      return ( 0 );
    }
  } else          /* 1d encoding */
  { EncoderState( tif )->refline = NULL; }
  return ( 1 );
}

/*
   CCITT Group 3 FAX Encoding.
*/

#define Fax3FlushBits(tif, sp) {        \
    if ((tif)->tif_rawcc >= (tif)->tif_rawdatasize)   \
      (void) TIFFFlushData1(tif);     \
    *(tif)->tif_rawcp++ = (tidataval_t) (sp)->data;   \
    (tif)->tif_rawcc++;         \
    (sp)->data = 0, (sp)->bit = 8;        \
  }
#define _FlushBits(tif) {         \
    if ((tif)->tif_rawcc >= (tif)->tif_rawdatasize)   \
      (void) TIFFFlushData1(tif);     \
    *(tif)->tif_rawcp++ = (tidataval_t) data;   \
    (tif)->tif_rawcc++;         \
    data = 0, bit = 8;          \
  }
static const int _msbmask[9] =
{ 0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff };
#define _PutBits(tif, bits, length) {       \
    while (length > bit) {          \
      data |= bits >> (length - bit);     \
      length -= bit;          \
      _FlushBits(tif);        \
    }             \
    data |= (bits & _msbmask[length]) << (bit - length);  \
    bit -= length;            \
    if (bit == 0)           \
      _FlushBits(tif);        \
  }

/*
   Write a variable-length bit-value to
   the output stream.  Values are
   assumed to be at most 16 bits.
*/
static void
Fax3PutBits( TIFF* tif, u_int bits, u_int length ) {
  Fax3CodecState* sp = EncoderState( tif );
  u_int bit = sp->bit;
  int data = sp->data;
  _PutBits( tif, bits, length );
  sp->data = data;
  sp->bit = bit;
}

/*
   Write a code to the output stream.
*/
#define putcode(tif, te)  Fax3PutBits(tif, (te)->code, (te)->length)

#ifdef FAX3_DEBUG
#define DEBUG_COLOR(w) (tab == TIFFFaxWhiteCodes ? w "W" : w "B")
#define DEBUG_PRINT(what,len) {           \
    int t;                \
    printf("%08X/%-2d: %s%5d\t", data, bit, DEBUG_COLOR(what), len);  \
    for (t = length-1; t >= 0; t--)         \
      putchar(code & (1<<t) ? '1' : '0');       \
    putchar('\n');              \
  }
#endif

/*
   Write the sequence of codes that describes
   the specified span of zero's or one's.  The
   appropriate table that holds the make-up and
   terminating codes is supplied.
*/
static void
putspan( TIFF* tif, int32 span, const tableentry* tab ) {
  Fax3CodecState* sp = EncoderState( tif );
  u_int bit = sp->bit;
  int data = sp->data;
  u_int code, length;
  while( span >= 2624 ) {
    const tableentry* te = &tab[63 + ( 2560 >> 6 )];
    code = te->code, length = te->length;
    #ifdef FAX3_DEBUG
    DEBUG_PRINT( "MakeUp", te->runlen );
    #endif
    _PutBits( tif, code, length );
    span -= te->runlen;
  }
  if( span >= 64 ) {
    const tableentry* te = &tab[63 + ( span >> 6 )];
    assert( te->runlen == 64 * ( span >> 6 ) );
    code = te->code, length = te->length;
    #ifdef FAX3_DEBUG
    DEBUG_PRINT( "MakeUp", te->runlen );
    #endif
    _PutBits( tif, code, length );
    span -= te->runlen;
  }
  code = tab[span].code, length = tab[span].length;
  #ifdef FAX3_DEBUG
  DEBUG_PRINT( "  Term", tab[span].runlen );
  #endif
  _PutBits( tif, code, length );
  sp->data = data;
  sp->bit = bit;
}

/*
   Write an EOL code to the output stream.  The zero-fill
   logic for byte-aligning encoded scanlines is handled
   here.  We also handle writing the tag bit for the next
   scanline when doing 2d encoding.
*/
static void
Fax3PutEOL( TIFF* tif ) {
  Fax3CodecState* sp = EncoderState( tif );
  u_int bit = sp->bit;
  int data = sp->data;
  u_int code, length, tparm;
  if( sp->b.groupoptions & GROUP3OPT_FILLBITS ) {
    /*
       Force bit alignment so EOL will terminate on
       a byte boundary.  That is, force the bit alignment
       to 16-12 = 4 before putting out the EOL code.
    */
    int align = 8 - 4;
    if( align != sp->bit ) {
      if( align > sp->bit ) {
        align = sp->bit + ( 8 - align );
      } else
      { align = sp->bit - align; }
      code = 0;
      tparm = align;
      _PutBits( tif, 0, tparm );
    }
  }
  code = EOL, length = 12;
  if( is2DEncoding( sp ) ) {
    code = ( code << 1 ) | ( sp->tag == G3_1D ), length++;
  }
  _PutBits( tif, code, length );
  sp->data = data;
  sp->bit = bit;
}

/*
   Reset encoding state at the start of a strip.
*/
static int
Fax3PreEncode( TIFF* tif, tsample_t s ) {
  Fax3CodecState* sp = EncoderState( tif );
  ( void ) s;
  assert( sp != NULL );
  sp->bit = 8;
  sp->data = 0;
  sp->tag = G3_1D;
  /*
     This is necessary for Group 4; otherwise it isn't
     needed because the first scanline of each strip ends
     up being copied into the refline.
  */
  if( sp->refline ) {
    _TIFFmemset( sp->refline, 0x00, sp->b.rowbytes );
  }
  if( is2DEncoding( sp ) ) {
    float res = tif->tif_dir.td_yresolution;
    /*
       The CCITT spec says that when doing 2d encoding, you
       should only do it on K consecutive scanlines, where K
       depends on the resolution of the image being encoded
       (2 for <= 200 lpi, 4 for > 200 lpi).  Since the directory
       code initializes td_yresolution to 0, this code will
       select a K of 2 unless the YResolution tag is set
       appropriately.  (Note also that we fudge a little here
       and use 150 lpi to avoid problems with units conversion.)
    */
    if( tif->tif_dir.td_resolutionunit == RESUNIT_CENTIMETER ) {
      res *= 2.54f;  /* convert to inches */
    }
    sp->maxk = ( res > 150 ? 4 : 2 );
    sp->k = sp->maxk - 1;
  } else
  { sp->k = sp->maxk = 0; }
  return ( 1 );
}

static const u_char zeroruns[256] = {
  8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, /* 0x00 - 0x0f */
  3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, /* 0x10 - 0x1f */
  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, /* 0x20 - 0x2f */
  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, /* 0x30 - 0x3f */
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 0x40 - 0x4f */
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 0x50 - 0x5f */
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 0x60 - 0x6f */
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 0x70 - 0x7f */
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x80 - 0x8f */
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x90 - 0x9f */
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xa0 - 0xaf */
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xb0 - 0xbf */
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xc0 - 0xcf */
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xd0 - 0xdf */
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xe0 - 0xef */
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xf0 - 0xff */
};
static const u_char oneruns[256] = {
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x00 - 0x0f */
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x10 - 0x1f */
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x20 - 0x2f */
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x30 - 0x3f */
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x40 - 0x4f */
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x50 - 0x5f */
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x60 - 0x6f */
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x70 - 0x7f */
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 0x80 - 0x8f */
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 0x90 - 0x9f */
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 0xa0 - 0xaf */
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 0xb0 - 0xbf */
  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, /* 0xc0 - 0xcf */
  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, /* 0xd0 - 0xdf */
  3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, /* 0xe0 - 0xef */
  4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 7, 8, /* 0xf0 - 0xff */
};

/*
   On certain systems it pays to inline
   the routines that find pixel spans.
*/
#ifdef VAXC
static  int32 find0span( u_char*, int32, int32 );
static  int32 find1span( u_char*, int32, int32 );
#pragma inline(find0span,find1span)
#endif

/*
   Find a span of ones or zeros using the supplied
   table.  The ``base'' of the bit string is supplied
   along with the start+end bit indices.
*/
INLINE static int32
find0span( u_char* bp, int32 bs, int32 be ) {
  int32 bits = be - bs;
  int32 n, span;
  bp += bs >> 3;
  /*
     Check partial byte on lhs.
  */
  if( bits > 0 && ( n = ( bs & 7 ) ) ) {
    span = zeroruns[( *bp << n ) & 0xff];
    if( span > 8 - n ) /* table value too generous */
    { span = 8 - n; }
    if( span > bits ) /* constrain span to bit range */
    { span = bits; }
    if( n + span < 8 ) /* doesn't extend to edge of byte */
    { return ( span ); }
    bits -= span;
    bp++;
  } else
  { span = 0; }
  if( bits >= 2 * 8 * sizeof( long ) ) {
    long* lp;
    /*
       Align to longword boundary and check longwords.
    */
    while( !isAligned( bp, long ) ) {
      if( *bp != 0x00 ) {
        return ( span + zeroruns[*bp] );
      }
      span += 8, bits -= 8;
      bp++;
    }
    lp = ( long* ) bp;
    while( bits >= 8 * sizeof( long ) && *lp == 0 ) {
      span += 8 * sizeof( long ), bits -= 8 * sizeof( long );
      lp++;
    }
    bp = ( u_char* ) lp;
  }
  /*
     Scan full bytes for all 0's.
  */
  while( bits >= 8 ) {
    if( *bp != 0x00 ) /* end of run */
    { return ( span + zeroruns[*bp] ); }
    span += 8, bits -= 8;
    bp++;
  }
  /*
     Check partial byte on rhs.
  */
  if( bits > 0 ) {
    n = zeroruns[*bp];
    span += ( n > bits ? bits : n );
  }
  return ( span );
}

INLINE static int32
find1span( u_char* bp, int32 bs, int32 be ) {
  int32 bits = be - bs;
  int32 n, span;
  bp += bs >> 3;
  /*
     Check partial byte on lhs.
  */
  if( bits > 0 && ( n = ( bs & 7 ) ) ) {
    span = oneruns[( *bp << n ) & 0xff];
    if( span > 8 - n ) /* table value too generous */
    { span = 8 - n; }
    if( span > bits ) /* constrain span to bit range */
    { span = bits; }
    if( n + span < 8 ) /* doesn't extend to edge of byte */
    { return ( span ); }
    bits -= span;
    bp++;
  } else
  { span = 0; }
  if( bits >= 2 * 8 * sizeof( long ) ) {
    long* lp;
    /*
       Align to longword boundary and check longwords.
    */
    while( !isAligned( bp, long ) ) {
      if( *bp != 0xff ) {
        return ( span + oneruns[*bp] );
      }
      span += 8, bits -= 8;
      bp++;
    }
    lp = ( long* ) bp;
    while( bits >= 8 * sizeof( long ) && *lp == ~0 ) {
      span += 8 * sizeof( long ), bits -= 8 * sizeof( long );
      lp++;
    }
    bp = ( u_char* ) lp;
  }
  /*
     Scan full bytes for all 1's.
  */
  while( bits >= 8 ) {
    if( *bp != 0xff ) /* end of run */
    { return ( span + oneruns[*bp] ); }
    span += 8, bits -= 8;
    bp++;
  }
  /*
     Check partial byte on rhs.
  */
  if( bits > 0 ) {
    n = oneruns[*bp];
    span += ( n > bits ? bits : n );
  }
  return ( span );
}

/*
   Return the offset of the next bit in the range
   [bs..be] that is different from the specified
   color.  The end, be, is returned if no such bit
   exists.
*/
#define finddiff(_cp, _bs, _be, _color) \
  (_bs + (_color ? find1span(_cp,_bs,_be) : find0span(_cp,_bs,_be)))
/*
   Like finddiff, but also check the starting bit
   against the end in case start > end.
*/
#define finddiff2(_cp, _bs, _be, _color) \
  (_bs < _be ? finddiff(_cp,_bs,_be,_color) : _be)

/*
   1d-encode a row of pixels.  The encoding is
   a sequence of all-white or all-black spans
   of pixels encoded with Huffman codes.
*/
static int
Fax3Encode1DRow( TIFF* tif, u_char* bp, uint32 bits ) {
  Fax3CodecState* sp = EncoderState( tif );
  int32 span;
  uint32 bs = 0;
  for( ;; ) {
    span = find0span( bp, bs, bits ); /* white span */
    putspan( tif, span, TIFFFaxWhiteCodes );
    bs += span;
    if( bs >= bits ) {
      break;
    }
    span = find1span( bp, bs, bits ); /* black span */
    putspan( tif, span, TIFFFaxBlackCodes );
    bs += span;
    if( bs >= bits ) {
      break;
    }
  }
  if( sp->b.mode & ( FAXMODE_BYTEALIGN | FAXMODE_WORDALIGN ) ) {
    if( sp->bit != 8 )    /* byte-align */
    { Fax3FlushBits( tif, sp ); }
    if( ( sp->b.mode & FAXMODE_WORDALIGN ) &&
        !isAligned( tif->tif_rawcp, uint16 ) ) {
      Fax3FlushBits( tif, sp );
    }
  }
  return ( 1 );
}

static const tableentry horizcode =
{ 3, 0x1 };   /* 001 */
static const tableentry passcode =
{ 4, 0x1 };   /* 0001 */
static const tableentry vcodes[7] = {
  { 7, 0x03 },  /* 0000 011 */
  { 6, 0x03 },  /* 0000 11 */
  { 3, 0x03 },  /* 011 */
  { 1, 0x1 },   /* 1 */
  { 3, 0x2 },   /* 010 */
  { 6, 0x02 },  /* 0000 10 */
  { 7, 0x02 }   /* 0000 010 */
};

/*
   2d-encode a row of pixels.  Consult the CCITT
   documentation for the algorithm.
*/
static int
Fax3Encode2DRow( TIFF* tif, u_char* bp, u_char* rp, uint32 bits ) {
#define PIXEL(buf,ix) ((((buf)[(ix)>>3]) >> (7-((ix)&7))) & 1)
  uint32 a0 = 0;
  uint32 a1 = ( PIXEL( bp, 0 ) != 0 ? 0 : finddiff( bp, 0, bits, 0 ) );
  uint32 b1 = ( PIXEL( rp, 0 ) != 0 ? 0 : finddiff( rp, 0, bits, 0 ) );
  uint32 a2, b2;
  for( ;; ) {
    b2 = finddiff2( rp, b1, bits, PIXEL( rp, b1 ) );
    if( b2 >= a1 ) {
      int32 d = b1 - a1;
      if( !( -3 <= d && d <= 3 ) ) { /* horizontal mode */
        a2 = finddiff2( bp, a1, bits, PIXEL( bp, a1 ) );
        putcode( tif, &horizcode );
        if( a0 + a1 == 0 || PIXEL( bp, a0 ) == 0 ) {
          putspan( tif, a1 - a0, TIFFFaxWhiteCodes );
          putspan( tif, a2 - a1, TIFFFaxBlackCodes );
        } else {
          putspan( tif, a1 - a0, TIFFFaxBlackCodes );
          putspan( tif, a2 - a1, TIFFFaxWhiteCodes );
        }
        a0 = a2;
      } else {      /* vertical mode */
        putcode( tif, &vcodes[d + 3] );
        a0 = a1;
      }
    } else {        /* pass mode */
      putcode( tif, &passcode );
      a0 = b2;
    }
    if( a0 >= bits ) {
      break;
    }
    a1 = finddiff( bp, a0, bits, PIXEL( bp, a0 ) );
    b1 = finddiff( rp, a0, bits, !PIXEL( bp, a0 ) );
    b1 = finddiff( rp, b1, bits, PIXEL( bp, a0 ) );
  }
  return ( 1 );
#undef PIXEL
}

/*
   Encode a buffer of pixels.
*/
static int
Fax3Encode( TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s ) {
  Fax3CodecState* sp = EncoderState( tif );
  ( void ) s;
  while( ( long )cc > 0 ) {
    if( ( sp->b.mode & FAXMODE_NOEOL ) == 0 ) {
      Fax3PutEOL( tif );
    }
    if( is2DEncoding( sp ) ) {
      if( sp->tag == G3_1D ) {
        if( !Fax3Encode1DRow( tif, bp, sp->b.rowpixels ) ) {
          return ( 0 );
        }
        sp->tag = G3_2D;
      } else {
        if( !Fax3Encode2DRow( tif, bp, sp->refline, sp->b.rowpixels ) ) {
          return ( 0 );
        }
        sp->k--;
      }
      if( sp->k == 0 ) {
        sp->tag = G3_1D;
        sp->k = sp->maxk - 1;
      } else
      { _TIFFmemcpy( sp->refline, bp, sp->b.rowbytes ); }
    } else {
      if( !Fax3Encode1DRow( tif, bp, sp->b.rowpixels ) ) {
        return ( 0 );
      }
    }
    bp += sp->b.rowbytes;
    cc -= sp->b.rowbytes;
  }
  return ( 1 );
}

static int
Fax3PostEncode( TIFF* tif ) {
  Fax3CodecState* sp = EncoderState( tif );
  if( sp->bit != 8 ) {
    Fax3FlushBits( tif, sp );
  }
  return ( 1 );
}

static void
Fax3Close( TIFF* tif ) {
  if( ( Fax3State( tif )->mode & FAXMODE_NORTC ) == 0 ) {
    Fax3CodecState* sp = EncoderState( tif );
    u_int code = EOL;
    u_int length = 12;
    int i;
    if( is2DEncoding( sp ) ) {
      code = ( code << 1 ) | ( sp->tag == G3_1D ), length++;
    }
    for( i = 0; i < 6; i++ ) {
      Fax3PutBits( tif, code, length );
    }
    Fax3FlushBits( tif, sp );
  }
}

static void
Fax3Cleanup( TIFF* tif ) {
  if( tif->tif_data ) {
    Fax3CodecState* sp = DecoderState( tif );
    if( sp->runs ) {
      _TIFFfree( sp->runs );
    }
    if( sp->refline ) {
      _TIFFfree( sp->refline );
    }
    if( Fax3State( tif )->subaddress ) {
      _TIFFfree( Fax3State( tif )->subaddress );
    }
    _TIFFfree( tif->tif_data );
    tif->tif_data = NULL;
  }
}

#define FIELD_BADFAXLINES (FIELD_CODEC+0)
#define FIELD_CLEANFAXDATA  (FIELD_CODEC+1)
#define FIELD_BADFAXRUN   (FIELD_CODEC+2)
#define FIELD_RECVPARAMS  (FIELD_CODEC+3)
#define FIELD_SUBADDRESS  (FIELD_CODEC+4)
#define FIELD_RECVTIME    (FIELD_CODEC+5)

#define FIELD_OPTIONS   (FIELD_CODEC+6)

static const TIFFFieldInfo faxFieldInfo[] = {
  {
    TIFFTAG_FAXMODE,     0, 0,  TIFF_ANY, FIELD_PSEUDO,
    FALSE,  FALSE,  "FaxMode"
  },
  {
    TIFFTAG_FAXFILLFUNC,   0, 0,  TIFF_ANY, FIELD_PSEUDO,
    FALSE,  FALSE,  "FaxFillFunc"
  },
  {
    TIFFTAG_BADFAXLINES,   1, 1,  TIFF_LONG,  FIELD_BADFAXLINES,
    TRUE, FALSE,  "BadFaxLines"
  },
  {
    TIFFTAG_BADFAXLINES,   1, 1,  TIFF_SHORT, FIELD_BADFAXLINES,
    TRUE, FALSE,  "BadFaxLines"
  },
  {
    TIFFTAG_CLEANFAXDATA,  1, 1,  TIFF_SHORT, FIELD_CLEANFAXDATA,
    TRUE, FALSE,  "CleanFaxData"
  },
  {
    TIFFTAG_CONSECUTIVEBADFAXLINES, 1, 1, TIFF_LONG,  FIELD_BADFAXRUN,
    TRUE, FALSE,  "ConsecutiveBadFaxLines"
  },
  {
    TIFFTAG_CONSECUTIVEBADFAXLINES, 1, 1, TIFF_SHORT, FIELD_BADFAXRUN,
    TRUE, FALSE,  "ConsecutiveBadFaxLines"
  },
  {
    TIFFTAG_FAXRECVPARAMS,   1, 1, TIFF_LONG, FIELD_RECVPARAMS,
    TRUE, FALSE,  "FaxRecvParams"
  },
  {
    TIFFTAG_FAXSUBADDRESS,  -1, -1, TIFF_ASCII,  FIELD_SUBADDRESS,
    TRUE, FALSE,  "FaxSubAddress"
  },
  {
    TIFFTAG_FAXRECVTIME,   1, 1, TIFF_LONG, FIELD_RECVTIME,
    TRUE, FALSE,  "FaxRecvTime"
  },
};
static const TIFFFieldInfo fax3FieldInfo[] = {
  {
    TIFFTAG_GROUP3OPTIONS,   1, 1,  TIFF_LONG,  FIELD_OPTIONS,
    FALSE,  FALSE,  "Group3Options"
  },
};
static const TIFFFieldInfo fax4FieldInfo[] = {
  {
    TIFFTAG_GROUP4OPTIONS,   1, 1,  TIFF_LONG,  FIELD_OPTIONS,
    FALSE,  FALSE,  "Group4Options"
  },
};
#define N(a)  (sizeof (a) / sizeof (a[0]))

static int
Fax3VSetField( TIFF* tif, ttag_t tag, va_list ap ) {
  Fax3BaseState* sp = Fax3State( tif );
  switch( tag ) {
    case TIFFTAG_FAXMODE:
      sp->mode = va_arg( ap, int );
      return ( 1 );   /* NB: pseudo tag */
    case TIFFTAG_FAXFILLFUNC:
      DecoderState( tif )->fill = va_arg( ap, TIFFFaxFillFunc );
      return ( 1 );   /* NB: pseudo tag */
    case TIFFTAG_GROUP3OPTIONS:
    case TIFFTAG_GROUP4OPTIONS:
      sp->groupoptions = va_arg( ap, uint32 );
      break;
    case TIFFTAG_BADFAXLINES:
      sp->badfaxlines = va_arg( ap, uint32 );
      break;
    case TIFFTAG_CLEANFAXDATA:
      sp->cleanfaxdata = ( uint16 ) va_arg( ap, int );
      break;
    case TIFFTAG_CONSECUTIVEBADFAXLINES:
      sp->badfaxrun = va_arg( ap, uint32 );
      break;
    case TIFFTAG_FAXRECVPARAMS:
      sp->recvparams = va_arg( ap, uint32 );
      break;
    case TIFFTAG_FAXSUBADDRESS:
      _TIFFsetString( &sp->subaddress, va_arg( ap, char* ) );
      break;
    case TIFFTAG_FAXRECVTIME:
      sp->recvtime = va_arg( ap, uint32 );
      break;
    default:
      return ( *sp->vsetparent )( tif, tag, ap );
  }
  TIFFSetFieldBit( tif, _TIFFFieldWithTag( tif, tag )->field_bit );
  tif->tif_flags |= TIFF_DIRTYDIRECT;
  return ( 1 );
}

static int
Fax3VGetField( TIFF* tif, ttag_t tag, va_list ap ) {
  Fax3BaseState* sp = Fax3State( tif );
  switch( tag ) {
    case TIFFTAG_FAXMODE:
      *va_arg( ap, int* ) = sp->mode;
      break;
    case TIFFTAG_FAXFILLFUNC:
      *va_arg( ap, TIFFFaxFillFunc* ) = DecoderState( tif )->fill;
      break;
    case TIFFTAG_GROUP3OPTIONS:
    case TIFFTAG_GROUP4OPTIONS:
      *va_arg( ap, uint32* ) = sp->groupoptions;
      break;
    case TIFFTAG_BADFAXLINES:
      *va_arg( ap, uint32* ) = sp->badfaxlines;
      break;
    case TIFFTAG_CLEANFAXDATA:
      *va_arg( ap, uint16* ) = sp->cleanfaxdata;
      break;
    case TIFFTAG_CONSECUTIVEBADFAXLINES:
      *va_arg( ap, uint32* ) = sp->badfaxrun;
      break;
    case TIFFTAG_FAXRECVPARAMS:
      *va_arg( ap, uint32* ) = sp->recvparams;
      break;
    case TIFFTAG_FAXSUBADDRESS:
      *va_arg( ap, char** ) = sp->subaddress;
      break;
    case TIFFTAG_FAXRECVTIME:
      *va_arg( ap, uint32* ) = sp->recvtime;
      break;
    default:
      return ( *sp->vgetparent )( tif, tag, ap );
  }
  return ( 1 );
}

static void
Fax3PrintDir( TIFF* tif, FILE* fd, long flags ) {
  Fax3BaseState* sp = Fax3State( tif );
  ( void ) flags;
  if( TIFFFieldSet( tif, FIELD_OPTIONS ) ) {
    const char* sep = " ";
    if( tif->tif_dir.td_compression == COMPRESSION_CCITTFAX4 ) {
      fprintf( fd, "  Group 4 Options:" );
      if( sp->groupoptions & GROUP4OPT_UNCOMPRESSED ) {
        fprintf( fd, "%suncompressed data", sep );
      }
    } else {
      fprintf( fd, "  Group 3 Options:" );
      if( sp->groupoptions & GROUP3OPT_2DENCODING ) {
        fprintf( fd, "%s2-d encoding", sep ), sep = "+";
      }
      if( sp->groupoptions & GROUP3OPT_FILLBITS ) {
        fprintf( fd, "%sEOL padding", sep ), sep = "+";
      }
      if( sp->groupoptions & GROUP3OPT_UNCOMPRESSED ) {
        fprintf( fd, "%suncompressed data", sep );
      }
    }
    fprintf( fd, " (%lu = 0x%lx)\n",
             ( u_long ) sp->groupoptions, ( u_long ) sp->groupoptions );
  }
  if( TIFFFieldSet( tif, FIELD_CLEANFAXDATA ) ) {
    fprintf( fd, "  Fax Data:" );
    switch( sp->cleanfaxdata ) {
      case CLEANFAXDATA_CLEAN:
        fprintf( fd, " clean" );
        break;
      case CLEANFAXDATA_REGENERATED:
        fprintf( fd, " receiver regenerated" );
        break;
      case CLEANFAXDATA_UNCLEAN:
        fprintf( fd, " uncorrected errors" );
        break;
    }
    fprintf( fd, " (%u = 0x%x)\n",
             sp->cleanfaxdata, sp->cleanfaxdata );
  }
  if( TIFFFieldSet( tif, FIELD_BADFAXLINES ) ) {
    fprintf( fd, "  Bad Fax Lines: %lu\n", ( u_long ) sp->badfaxlines );
  }
  if( TIFFFieldSet( tif, FIELD_BADFAXRUN ) )
    fprintf( fd, "  Consecutive Bad Fax Lines: %lu\n",
             ( u_long ) sp->badfaxrun );
  if( TIFFFieldSet( tif, FIELD_RECVPARAMS ) )
    fprintf( fd, "  Fax Receive Parameters: %08lx\n",
             ( u_long ) sp->recvparams );
  if( TIFFFieldSet( tif, FIELD_SUBADDRESS ) ) {
    fprintf( fd, "  Fax SubAddress: %s\n", sp->subaddress );
  }
  if( TIFFFieldSet( tif, FIELD_RECVTIME ) )
    fprintf( fd, "  Fax Receive Time: %lu secs\n",
             ( u_long ) sp->recvtime );
}

static int
InitCCITTFax3( TIFF* tif ) {
  Fax3BaseState* sp;
  /*
     Allocate state block so tag methods have storage to record values.
  */
  tif->tif_data = ( tidata_t )
                  _TIFFmalloc( sizeof( Fax3CodecState ) );
  if( tif->tif_data == NULL ) {
    TIFFError( "TIFFInitCCITTFax3",
               "%s: No space for state block", tif->tif_name );
    return ( 0 );
  }
  sp = Fax3State( tif );
  sp->rw_mode = tif->tif_mode;
  /*
     Merge codec-specific tag information and
     override parent get/set field methods.
  */
  _TIFFMergeFieldInfo( tif, faxFieldInfo, N( faxFieldInfo ) );
  sp->vgetparent = tif->tif_tagmethods.vgetfield;
  tif->tif_tagmethods.vgetfield = Fax3VGetField;  /* hook for codec tags */
  sp->vsetparent = tif->tif_tagmethods.vsetfield;
  tif->tif_tagmethods.vsetfield = Fax3VSetField;  /* hook for codec tags */
  tif->tif_tagmethods.printdir = Fax3PrintDir;  /* hook for codec tags */
  sp->groupoptions = 0;
  sp->recvparams = 0;
  sp->subaddress = NULL;
  tif->tif_flags |= TIFF_NOBITREV;  /* decoder does bit reversal */
  DecoderState( tif )->runs = NULL;
  TIFFSetField( tif, TIFFTAG_FAXFILLFUNC, _TIFFFax3fillruns );
  EncoderState( tif )->refline = NULL;
  /*
     Install codec methods.
  */
  tif->tif_setupdecode = Fax3SetupState;
  tif->tif_predecode = Fax3PreDecode;
  tif->tif_decoderow = Fax3Decode1D;
  tif->tif_decodestrip = Fax3Decode1D;
  tif->tif_decodetile = Fax3Decode1D;
  tif->tif_setupencode = Fax3SetupState;
  tif->tif_preencode = Fax3PreEncode;
  tif->tif_postencode = Fax3PostEncode;
  tif->tif_encoderow = Fax3Encode;
  tif->tif_encodestrip = Fax3Encode;
  tif->tif_encodetile = Fax3Encode;
  tif->tif_close = Fax3Close;
  tif->tif_cleanup = Fax3Cleanup;
  return ( 1 );
}

int
TIFFInitCCITTFax3( TIFF* tif, int scheme ) {
  if( InitCCITTFax3( tif ) ) {
    _TIFFMergeFieldInfo( tif, fax3FieldInfo, N( fax3FieldInfo ) );
    /*
       The default format is Class/F-style w/o RTC.
    */
    return TIFFSetField( tif, TIFFTAG_FAXMODE, FAXMODE_CLASSF );
  } else
  { return ( 0 ); }
}

/*
   CCITT Group 4 (T.6) Facsimile-compatible
   Compression Scheme Support.
*/

#define SWAP(t,a,b) { t x; x = (a); (a) = (b); (b) = x; }
/*
   Decode the requested amount of G4-encoded data.
*/
static int
Fax4Decode( TIFF* tif, tidata_t buf, tsize_t occ, tsample_t s ) {
  DECLARE_STATE_2D( tif, sp, "Fax4Decode" );
  ( void ) s;
  CACHE_STATE( tif, sp );
  while( ( long )occ > 0 ) {
    a0 = 0;
    RunLength = 0;
    pa = thisrun = sp->curruns;
    pb = sp->refruns;
    b1 = *pb++;
    #ifdef FAX3_DEBUG
    printf( "\nBitAcc=%08X, BitsAvail = %d\n", BitAcc, BitsAvail );
    printf( "-------------------- %d\n", tif->tif_row );
    fflush( stdout );
    #endif
    EXPAND2D( EOFG4 );
    if( EOLcnt ) {
      goto EOFG4;
    }
    ( *sp->fill )( buf, thisrun, pa, lastx );
    SETVAL( 0 );  /* imaginary change for reference */
    SWAP( uint32*, sp->curruns, sp->refruns );
    buf += sp->b.rowbytes;
    occ -= sp->b.rowbytes;
    continue;
  EOFG4:
    NeedBits16( 13, BADG4 );
  BADG4:
    #ifdef FAX3_DEBUG
    if( GetBits( 13 ) != 0x1001 ) {
      fputs( "Bad RTC\n", stderr );
    }
    #endif
    ClrBits( 13 );
    ( *sp->fill )( buf, thisrun, pa, lastx );
    UNCACHE_STATE( tif, sp );
    return ( -1 );
  }
  UNCACHE_STATE( tif, sp );
  return ( 1 );
}
#undef  SWAP

/*
   Encode the requested amount of data.
*/
static int
Fax4Encode( TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s ) {
  Fax3CodecState *sp = EncoderState( tif );
  ( void ) s;
  while( ( long )cc > 0 ) {
    if( !Fax3Encode2DRow( tif, bp, sp->refline, sp->b.rowpixels ) ) {
      return ( 0 );
    }
    _TIFFmemcpy( sp->refline, bp, sp->b.rowbytes );
    bp += sp->b.rowbytes;
    cc -= sp->b.rowbytes;
  }
  return ( 1 );
}

static int
Fax4PostEncode( TIFF* tif ) {
  Fax3CodecState *sp = EncoderState( tif );
  /* terminate strip w/ EOFB */
  Fax3PutBits( tif, EOL, 12 );
  Fax3PutBits( tif, EOL, 12 );
  if( sp->bit != 8 ) {
    Fax3FlushBits( tif, sp );
  }
  return ( 1 );
}

int
TIFFInitCCITTFax4( TIFF* tif, int scheme ) {
  if( InitCCITTFax3( tif ) ) { /* reuse G3 support */
    _TIFFMergeFieldInfo( tif, fax4FieldInfo, N( fax4FieldInfo ) );
    tif->tif_decoderow = Fax4Decode;
    tif->tif_decodestrip = Fax4Decode;
    tif->tif_decodetile = Fax4Decode;
    tif->tif_encoderow = Fax4Encode;
    tif->tif_encodestrip = Fax4Encode;
    tif->tif_encodetile = Fax4Encode;
    tif->tif_postencode = Fax4PostEncode;
    /*
       Suppress RTC at the end of each strip.
    */
    return TIFFSetField( tif, TIFFTAG_FAXMODE, FAXMODE_NORTC );
  } else
  { return ( 0 ); }
}

/*
   CCITT Group 3 1-D Modified Huffman RLE Compression Support.
   (Compression algorithms 2 and 32771)
*/

/*
   Decode the requested amount of RLE-encoded data.
*/
static int
Fax3DecodeRLE( TIFF* tif, tidata_t buf, tsize_t occ, tsample_t s ) {
  DECLARE_STATE( tif, sp, "Fax3DecodeRLE" );
  int mode = sp->b.mode;
  ( void ) s;
  CACHE_STATE( tif, sp );
  thisrun = sp->curruns;
  while( ( long )occ > 0 ) {
    a0 = 0;
    RunLength = 0;
    pa = thisrun;
    #ifdef FAX3_DEBUG
    printf( "\nBitAcc=%08X, BitsAvail = %d\n", BitAcc, BitsAvail );
    printf( "-------------------- %d\n", tif->tif_row );
    fflush( stdout );
    #endif
    EXPAND1D( EOFRLE );
    ( *sp->fill )( buf, thisrun, pa, lastx );
    /*
       Cleanup at the end of the row.
    */
    if( mode & FAXMODE_BYTEALIGN ) {
      int n = BitsAvail - ( BitsAvail & ~ 7 );
      ClrBits( n );
    } else if( mode & FAXMODE_WORDALIGN ) {
      int n = BitsAvail - ( BitsAvail & ~ 15 );
      ClrBits( n );
      if( BitsAvail == 0 && !isAligned( cp, uint16 ) ) {
        cp++;
      }
    }
    buf += sp->b.rowbytes;
    occ -= sp->b.rowbytes;
    continue;
  EOFRLE:       /* premature EOF */
    ( *sp->fill )( buf, thisrun, pa, lastx );
    UNCACHE_STATE( tif, sp );
    return ( -1 );
  }
  UNCACHE_STATE( tif, sp );
  return ( 1 );
}

int
TIFFInitCCITTRLE( TIFF* tif, int scheme ) {
  if( InitCCITTFax3( tif ) ) { /* reuse G3 support */
    tif->tif_decoderow = Fax3DecodeRLE;
    tif->tif_decodestrip = Fax3DecodeRLE;
    tif->tif_decodetile = Fax3DecodeRLE;
    /*
       Suppress RTC+EOLs when encoding and byte-align data.
    */
    return TIFFSetField( tif, TIFFTAG_FAXMODE,
                         FAXMODE_NORTC | FAXMODE_NOEOL | FAXMODE_BYTEALIGN );
  } else
  { return ( 0 ); }
}

int
TIFFInitCCITTRLEW( TIFF* tif, int scheme ) {
  if( InitCCITTFax3( tif ) ) { /* reuse G3 support */
    tif->tif_decoderow = Fax3DecodeRLE;
    tif->tif_decodestrip = Fax3DecodeRLE;
    tif->tif_decodetile = Fax3DecodeRLE;
    /*
       Suppress RTC+EOLs when encoding and word-align data.
    */
    return TIFFSetField( tif, TIFFTAG_FAXMODE,
                         FAXMODE_NORTC | FAXMODE_NOEOL | FAXMODE_WORDALIGN );
  } else
  { return ( 0 ); }
}
#endif /* CCITT_SUPPORT */
